Many hair treatment processes, such as permanent waving or curling, bleaching, coloring or dyeing, straightening and shampooing cause a degree of damage to the hair, leaving it with a harsh feel and often making it difficult to comb or manage in subsequent hair cutting, styling or general daily care. In order to overcome these problems, it has been common to use various softening agents in the form of hair conditioners or creme rinses, usually applied to the hair in a separate step after the treatment which caused the problem. Cationic softening agents have been most popular for this purpose, especially the cationic fatty quaternary compounds having fatty chain lengths of about 8 to 18 carbon atoms. Most of the known softeners or hair conditioners do not work well when incorporated into other hair treatment compositions, including shampoos as well as waving, coloring, bleaching and straightening compositions, and it is for this reason that the hair conditioners are practical only as a special post-treatment composition.
According to Phillip E. Sokol in U.S. Pat. No. 3,919,808 and Du Y. Hsiung et al in U.S. Pat. No. 4,175,572, it has been possible to use polymers of diallyl dialkyl ammonium salts, for example a polymer of diallyldimethylammonium chloride, in order to soften the hair during such known treatments as curling, bleaching, coloring and straightening of hair. The Sokol patent is of particular interest because it describes the state of the art during the early 1970's and the lack of any real solution to the problem of providing a hair softener or conditioner which is compatible with other hair treating processes or compositions. Sokol provides only one solution to the known problems and demands the use of a relatively expensive class of polymers or copolymers, prepared according to Butler et al in U.S. Pat. No. 2,926,161, using a free radical generating polymerization catalyst such as a peroxide, and then adopting an anion exchange column to exchange the anion, if desired, according to U.S. Pat. No. 3,288,770 and U.S. Pat. No. 3,412,019.
The Sokol patent does provide useful definitions of various hair treatment compositions, and this subject matter is therefore incorporated herein by reference as fully as if set forth in its entirety, since the present invention is also directed to the same types of compositions.
It is an object of the present invention to provide an improved method of softening or conditioning hair by using a class of cationic compounds which are highly compatible with the known compositions and methods used to curl, wave, bleach, dye, color, straighten and/or shampoo the hair. It is also an object of the invention to provide such a conditioner or softener which can be used before, during or after other hair treatments, so that the hair is easier to manage and comb at any stage during its treatment or care. It is also an object of the invention to provide a cationic conditioner or softener and methods for its application whereby the conditioned hair will retain its soft feel and manageability for a relatively long period of time even after final rinsing and drying.